1. FIELD OF THE INVENTION
The invention concerns detection of the proximity of change of phase within a fluid.
This invention should be especially useful when it is necessary to detect the apparition or the imminence of local boiling phenomenon within a liquid or more generally the presence of bubbles within the liquid.
Among the fields in which the invention is particularly suitable for use, there is the field of nuclear Pressurized Water Reactors, where temperature and pressure conditions generating a local boiling of the coolant of the reactor have to be avoided, since damage to the nuclear fuel assemblies could happen.
2. STATE OF THE ART
Various methods have existed for a long time for determining the occurrence of a phase change. For instance, there is disclosed in European Pat. No. 056 454 a method for finding the boiling point of a brake oil. The method includes delivering electrical current to a sensor for heating it until a temperature variation curve shows a change revealing boiling.
This has drawbacks, for instance, it does not allow detection of the imminence of boiling, the object of the invention being to find the boiling point by increasing the voltage until obtaining the change of phases. In a general way, none of the previous methods teaches or suggests monitoring of change of phase in a way which could prevent, particularly in the case of nuclear reaction, operational problems and safety hazards.